My current het relationship is going fine, but lately I've been having these odd fantasies about girls. I really think I'd rather BE these girls than be WITH these girls, but I don't know.
Y'all really didn't hesitate to hit me with your difficult stuff, did you.
I'm not sure that you wanted me to answer anything, as you didn't really include a question, so why don't I just throw out a few things for you to think about.
I've wondered the same thing about whether I want to be certain girls or be with them, though for me it's more about where I fall on the butch/femme scale than it is about whether I'm gay or not, so I feel you. That's something you have to figure out on your own, but you might want to think about your fantasies. What are they about? Are they about conversations and coolness, or are they about some girl's body and yours, without much accompaniment? If it's the latter, I'd say you want to be with 'em. If it's the former, it might be more about being like them. Also, there's nothing that says that you can't want both at the same time. My greatest loves and crushes (both male and female) have been like that; a big mess of longing and longing to be like. I don't think there's anything wrong with that. It's awesome to admire the people you're attracted to.
How's your sex life? It's possible that you're fantasizing about women 'cause you feel like something is lacking in what you have now. Do you obsess, or are these passing fancies? How fretful were you feeling when you asked this question? I suspect, based on almost nothing at all (magic 8-ball), that this isn't crucial for you, and that you're mostly just curious about what I'll say.
Finally, here's what I think about sexual orientation: Some of us just know what we are from the time we're kids. We are straight, or we are gay, and it's crystal clear, or it tends to hit us as an epiphany after several failed and empty relationships with men or women (alright, that's more like what happens to gay people, 'cause most of us start out assuming we're straight, but I do try to be open-minded). The rest of us, myself included, don't get smacked in the head with our orientation and suddenly learn how to love and be happy in our relationships. We decide as we go. We think about what we have, and how it feels to us. We think about what we want next. We think about the sex, and what we like. We think about the way we relate to our partner, and what that has to do with gender. We make it up, really. That's alright, too. Being with a man now doesn't mean that you're utterly straight. Fantasizing about women doesn't mean that you're at all gay. You are just who you are. Hanne Blank wrote this great essay about sexuality that I always tell people to read when I get into discussions about this sort of thing with them. Check it out. And don't worry about your fantasies. I say enjoy 'em.